Thanks. I couldn't immediately see how to do what I want with your solution, but the DBI recipes reference gave me everything I needed. I'll keep trying with your advice, though, as the purpose is to understand (the live DB & VB front end has been supporting about 20 users for about 18 months). I'm still rather mixed up about the array instructions, but I expect that I'll be able to sort myself out with more reading.
I am using strict, warnings and diagnostics in all my files. If I didn't mention it in my somewhat rambling post, my apologies.